What you say is true. However there is no limit (in game rules) on how many times you can wound a character (it's the same with burdens). There's only an effect performed when number of wounds equals vitality or number of burdens equals resistance, but you can always choose any alive character to take any number of wounds - how you deal with them later and if you can save that character from death is up to you.
Threats or exertions are another thing, as the rules state what is the limit of adding threats or exerting characters, that's why you are sometimes forced to add burdens with Isildur, BoH or Gimli, BoG. But with Boromir, BoC both choices are always possible, though each of them can sometimes cause the end of the game.
Ok, what you say seems fine, just one more fine detail, to make sure I get this right this time. Can you choose to assign a wound to a character that has 0 vitality.
Here is an example:
Your Aragorn is dying due to having wounds=vitality (0 vitality). Your opponent has "
Held Ground" in play and chooses to use "is about to be killed" trigger (so your companion is in play with 0 vitality, while it resolves). Now, your opponent removes one threat (lets assume there were 3 threats) and discards two possessions. Lets assume one of the possessions he discards is "
Herugrim" on your exhausted "Theoden". This causes the Theoden to die due to having 0 vitality. Because your character (Theoden) died, you have to assign 2 remaining threats. Can you assign one (or both of them) to your (still in the process of dying) Aragorn?